Table 3.

Effects estimates of the responses obtained of the 2⁴-experimental design for partition coefficient (K), top activity yield (Y), purification factor in the top phase (PF), selectivity (S) of xylanase extraction by PEG/citrate ATPS

	K	Y	PF	S
1—M PEG	−4.81*	−1.46	−2.60	−1.60
2—C PEG	1.35	0.32	−7.18*	−0.62
3—C C	7.54*	−3.64*	−10.0*	−1.33
4—pH	0.95	−1.35	−2.17	−0.22
1*2	5.08*	1.21	1.12	2.14
1*3	4.97*	2.29	2.24	2.17
1*4	2.00	2.08	2.44	0.76
2*3	1.65	0.24	7.31*	2.89
2*4	−2.17	−0.56	−7.56*	−4.35*
3*4	−3.20	0.99	2.43	−1.47

* Statistically significant value (at the 95 % confidence level, p < 0.05)